1. Volume 49, Issue 6, Pages 1167-1175 (March 2013)
AMPK-Dependent Degradation of TXNIP upon Energy Stress Leads to Enhanced Glucose Uptake via GLUT1 
Ning Wu, Bin Zheng, Adam Shaywitz, Yossi Dagon, Christine Tower, Gary Bellinger, Che-Hung Shen, Jennifer Wen, John Asara, Timothy E. McGraw, Barbara B. Kahn, Lewis C. Cantley 
Molecular Cell 
Volume 49, Issue 6, Pages (March 2013)
DOI: /j.molcel
Copyright © 2013 Elsevier Inc. Terms and Conditions

2. Figure 1 AMPK-Dependent TXNIP Phosphorylation
Western blots of total cell lysates probed with TXNIP, phosphoAMPK (T172), total AMPK, phosphoACC (S79), and total ACC antibodies under various conditions. The activation of AMPK causes an upshift in TXNIP mobility.
(A) HepG2 cells were glucose starved for 20’ and 40’ in Dulbecco's modified Eagle's medium with no glucose and 10% dialyzed fetal bovine serum.
(B) HepG2 cells were treated with AMPK activators: 25 mM 2DG for 10’, 2 mM AICAR for 60’, 1 mM A for 30’, and 2 mM phenformin for 30’.
(C) AMPK, WT, and DKO (double knockout for both α1 and α2) MEFs were treated with 25 mM 2DG for 10’.
(D) λ-phosphatase treatment of endogenous TXNIP immunoprecipitated from HepG2 cells treated with 25 mM 2DG abolishes the upshift in TXNIP mobility.
Molecular Cell  , DOI: ( /j.molcel )
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3. Figure 2
AMPK Phosphorylation of TXNIP on S308 Accelerates Its Degradation
(A and B) Western blots showing decreasing TXNIP levels after AMPK activation in (A) primary rat hepatocytes and (B) AMPK WT and DKO MEFs treated with 1 mM A for 0’, 30’, and 60’.
(C) qRT-PCR analysis of TXNIP mRNA from RNA isolated from HepG2 cells after various treatments indicating that short-term activation of AMPK (e.g., with A769662) does not decrease TXNIP mRNA level, whereas glucose starvation does, as reported before. The values are the average of triplicates ± SD.
(D) HepG2 cells were pretreated with cycloheximide (CHX) for 20’ to stop protein synthesis and then stimulated with A to activate AMPK. Lysates harvested at the indicated time points show an increased rate of TXNIP protein degradation with AMPK activation.
(E) Domain structure of TXNIP and multiple sequence alignment of human, rat, and mouse TXNIP and human ARRDC4 around Ser308.
(F) HepG2 cells that stably express vector control, HA-WT, or HA-S308A TXNIP treated with 25 mM 2DG for 10’ show that the S308A mutation abolishes the phosphorylation-induced protein mobility upshift after AMPK activation.
(G) HepG2 cells the stably express vector control, HA-WT, or HA-S308A TXNIP were treated with 1 mM A for 0’, 30’, and 60’. HA-S308A TXNIP protein is degraded at a slower rate than both HA-WT cells and endogenous TXNIP. ∗, HA-tagged protein; ∗∗, endogenous protein.
Molecular Cell  , DOI: ( /j.molcel )
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4. Figure 3 Dual Localization of TXNIP
(A) Confocal live-cell images of HepG2 cells stably expressing GFP-TXNIP and Histone2B-mCherry show plasma membrane localization of TXNIP in addition to its nuclear localization, which was reported before.
(B) TIRF live-cell images of HepG2 cells stably expressing GFP-TXNIP and mCherry-clathrin light chain (CLC) show some TXNIP protein localization in clathrin-coated pits (CCP).
(C) HepG2 cells stably expressing GFP-TXNIP and mCherry-CLC were labeled with Alexa647-transferrin at 4°C. After excess transferrin was rinsed off, time-lapse images were taken at room temperature to capture endocytosis events with a confocal microscope. For every time point, there was a 2–3 s delay between each fluorophore. GFP was followed by mCherry and then Alexa647. The arrow points to an endocytosed CCP that contained both GFP-TXNIP and Alexa647-transferrin. This sequence is also shown in Movie S3. The scale bar represents 1 μM.
(D) A western blot of HA IP of lysates from the mouse liver expressing adenoviral HA-TXNIP probed with clathrin heavy chain (CHC) and adaptor AP2 μ subunit (AP2M) antibodies. ∗, HA-tagged protein; ∗∗, endogenous protein.
(E) Multiple sequence alignment of the di-leucine motif in various clathrin-interacting proteins.
(F) Confocal and TIRF live-cell images of HepG2 cells stably expressing GFP-WT or GFP-L351AL352A TXNIP show that the LL-to-AA mutation abolished TXNIP localization to the CCP but not to the plasma membrane.
Molecular Cell  , DOI: ( /j.molcel )
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5. Figure 4 TXNIP Regulation of GLUT1
(A–C) Stable HepG2 cells that express control shRNA construct (GFPsh) or TXNIP knockdown shRNAs (sh1 and sh2) or knockdown cells reconstituted with HA-WT TXNIP construct that is resistant to sh1 (WT/sh1) were generated. Cells were examined for (A) GLUT1 protein levels by western blot, (B) GLUT1 mRNA levels by qRT-PCR normalized to GFPsh control cells, and (C) relative rate of glucose uptake in media with 2 mM glucose with a trace amount of 3H-2DG normalized to GFPsh control cells. The average values of triplicate experiments (± SD) are reported.
(D) HepG2 control cells and cells that stably express Flag-GLUT1 were treated with either water or 25 mM 2DG for 10’. Flag-tag IP was carried out with the cell lysates to test the interaction with endogenous TXNIP.
(E) HepG2 cells that stably express both Flag-GLUT1 and HA-TXNIP WT or both Flag-GLUT1 and HA-TXNIP S308A mutant were treated for 10’ with water, 5 mM 2DG, or 20 mM 2DG. Flag-tag IP was carried out to check for the effect of S308 phosphorylation on GLUT1 and TXNIP interaction.
(F) HA-GLUT1 endocytosis assay in TRVb-1 cells transiently transfected with HA-GLUT1, HA-GLUT1 and GFP-TXNIP WT, or HA-GLUT1 and GFP-TXNIP AA constructs. Cells were incubated with an antibody against HA-tag on the first exofacial loop of GLUT1 at 37°C and fixed after each time point. The cell surface HA-GLUT1 is labeled with the Cy5 secondary antibody, whereas the endocytosed HA-GLUT1 is labeled with the Cy3 secondary antibody. The ratio of Cy3-to-Cy5 fluorescence signal was reported as the ratio of internalized-to-surface HA-GLUT1 and plotted versus time ± SEM. R2 of the linear regression lines are shown. The data are from a representative experiment.
(G) Relative endocytosis rates calculated from the slopes of linear regression from data in (F) normalized to HA-GLUT1 control.
Molecular Cell  , DOI: ( /j.molcel )
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